/*
 * NOTE: This endpoint is now mostly for backward compatibility.
 * The main email list API (/api/courrier) now fetches full email content,
 * so individual email fetching is typically not needed.
 * This is kept for cases where individual email access is still required
 * or when using older client code.
 */

import { NextResponse } from 'next/server';
import { ImapFlow } from 'imapflow';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/app/api/auth/[...nextauth]/route';
import { prisma } from '@/lib/prisma';
import { simpleParser } from 'mailparser';

// Simple in-memory cache for email content
const emailContentCache = new Map<string, any>();

export async function GET(
  request: Request,
  { params }: { params: { id: string } }
) {
  try {
    const session = await getServerSession(authOptions);
    if (!session || !session.user?.id) {
      return NextResponse.json(
        { error: "Not authenticated" },
        { status: 401 }
      );
    }

    const { id } = params;
    if (!id) {
      return NextResponse.json(
        { error: "Missing email ID" },
        { status: 400 }
      );
    }

    // Get mail credentials
    const credentials = await prisma.mailCredentials.findUnique({
      where: {
        userId: session.user.id,
      },
    });

    if (!credentials) {
      return NextResponse.json(
        { error: "No mail credentials found" },
        { status: 404 }
      );
    }

    const { searchParams } = new URL(request.url);
    const folder = searchParams.get("folder") || "INBOX";

    // Create IMAP client
    let imapClient: any = null;
    try {
      imapClient = new ImapFlow({
        host: credentials.host,
        port: credentials.port,
        secure: true,
        auth: {
          user: credentials.email,
          pass: credentials.password,
        },
        logger: false,
      });

      await imapClient.connect();
      console.log(`Connected to IMAP server to fetch full email ${id}`);

      // Select mailbox
      const mailboxData = await imapClient.mailboxOpen(folder);
      console.log(`Opened mailbox ${folder} to fetch email ${id}`);

      // Fetch the complete email with its source
      const message = await imapClient.fetchOne(Number(id), {
        source: true,
        envelope: true
      });

      if (!message) {
        return NextResponse.json(
          { error: "Email not found" },
          { status: 404 }
        );
      }

      const { source, envelope } = message;
      
      // Parse the full email content
      const parsedEmail = await simpleParser(source.toString());
      
      // Return only the content
      return NextResponse.json({
        id,
        subject: envelope.subject,
        content: parsedEmail.html || parsedEmail.textAsHtml || parsedEmail.text || '',
        contentFetched: true
      });
    } catch (error: any) {
      console.error("Error fetching email content:", error);
      return NextResponse.json(
        { error: "Failed to fetch email content", message: error.message },
        { status: 500 }
      );
    } finally {
      // Close the mailbox and connection
      if (imapClient) {
        try {
          await imapClient.mailboxClose();
          await imapClient.logout();
        } catch (e) {
          console.error("Error closing IMAP connection:", e);
        }
      }
    }
  } catch (error: any) {
    console.error("Error in GET:", error);
    return NextResponse.json(
      { error: "Internal server error", message: error.message },
      { status: 500 }
    );
  }
}

// Add a route to mark email as read
export async function POST(
  request: Request,
  { params }: { params: { id: string } }
) {
  try {
    const session = await getServerSession(authOptions);
    if (!session || !session.user?.id) {
      return NextResponse.json(
        { error: "Not authenticated" },
        { status: 401 }
      );
    }

    const { id } = params;
    if (!id) {
      return NextResponse.json(
        { error: "Missing email ID" },
        { status: 400 }
      );
    }

    const { action } = await request.json();
    
    if (action !== 'mark-read' && action !== 'mark-unread') {
      return NextResponse.json(
        { error: "Invalid action. Supported actions: mark-read, mark-unread" },
        { status: 400 }
      );
    }

    // Get mail credentials
    const credentials = await prisma.mailCredentials.findUnique({
      where: {
        userId: session.user.id,
      },
    });

    if (!credentials) {
      return NextResponse.json(
        { error: "No mail credentials found" },
        { status: 404 }
      );
    }

    const { searchParams } = new URL(request.url);
    const folder = searchParams.get("folder") || "INBOX";

    // Create IMAP client
    let imapClient: any = null;
    try {
      imapClient = new ImapFlow({
        host: credentials.host,
        port: credentials.port,
        secure: true,
        auth: {
          user: credentials.email,
          pass: credentials.password,
        },
        logger: false,
      });

      await imapClient.connect();

      // Select mailbox
      await imapClient.mailboxOpen(folder);

      // Set flag based on action
      if (action === 'mark-read') {
        await imapClient.messageFlagsAdd(Number(id), ['\\Seen']);
      } else {
        await imapClient.messageFlagsRemove(Number(id), ['\\Seen']);
      }

      return NextResponse.json({ success: true });
    } catch (error: any) {
      console.error(`Error ${action === 'mark-read' ? 'marking email as read' : 'marking email as unread'}:`, error);
      return NextResponse.json(
        { error: `Failed to ${action === 'mark-read' ? 'mark email as read' : 'mark email as unread'}`, message: error.message },
        { status: 500 }
      );
    } finally {
      // Close the mailbox and connection
      if (imapClient) {
        try {
          await imapClient.mailboxClose();
          await imapClient.logout();
        } catch (e) {
          console.error("Error closing IMAP connection:", e);
        }
      }
    }
  } catch (error: any) {
    console.error("Error in POST:", error);
    return NextResponse.json(
      { error: "Internal server error", message: error.message },
      { status: 500 }
    );
  }
}